Many things that are considered vital to our everyday lives require energy. Computers, cell phones, light bulbs, cars, communication systems, etc., all require energy to operate. Energy, however, is not free. Energy must come from somewhere. Energy also comes at a cost, which can be expressed both economically and environmentally. Unfortunately, the cost of energy is increasing.
Because of the economic and/or environmental cost of energy, research is being done to discover how to improve the ways that energy is used. More specifically, research is being done to improve the efficiency at which energy is used, stored, and generated.
Improving the way that energy is used can include the use of energy storage devices. Energy storage devices come in different forms and store energy in different ways. Batteries, for instance, store energy chemically and are increasingly rechargeable. Other devices such as flywheels may store energy kinetically.
Conventional energy storage devices typically have limits on the amount of energy that can be stored. These limits are often associated with physical and/or chemical characteristics of the energy storage device. In other words, the characteristics of energy storage devices themselves often place limits on the energy storing capabilities. Overcharging a battery, for instance, often reduces the effectiveness of the battery and may render the battery inoperable or unsafe. As a result, battery chargers are often designed to stop the charging process before overcharging can occur.
The energy storage capability of flywheels are similarly limited. While the kinetic energy stored in a flywheel can be augmented by increasing the rotational velocity of the flywheel, storing too much energy in the flywheel often results in the destruction of the flywheel itself. As a result, the amount of energy that can be stored is limited. In addition, energy storage devices often suffer from parasitic leaks that drain the stored energy. The bearings in a conventional flywheel, for instance, create a drag that drains the stored energy over time.